Boost Pressure Sensor

This procedure covers removal and installation of the boost pressure sensor on the 2019 Mercedes-Benz G-Class with 4.0L Turbo V8 engine.

Warnings

Tools required

Parts

• Boost pressure sensor × 1 — A0009053503 or equivalent
• Sensor O-ring seal × 1 — Use OEM specification

Preparation

1. Ensure engine is completely cool to the touch
2. Open hood and secure in upright position
3. Disconnect negative battery terminal and wait 2 minutes for system capacitors to discharge
4. Locate boost pressure sensor on the intake air duct between turbocharger outlet and throttle body on driver's side of engine

Procedure

1. 1

   Access Sensor Location
   Remove the engine cover by pulling upward on the front and rear mounting points to release the rubber grommets. Set cover aside. Identify the boost pressure sensor mounted on the charge air duct. The sensor is a black plastic component with a single electrical connector and is secured by a mounting bolt. Note: Verify correct part number via VIN with a Mercedes-Benz dealer or EPC; do not rely on an unverified number.
2. 2

   Clean Work Area
   Use compressed air to blow away any dirt, debris, or oil residue from around the sensor mounting area. This prevents contamination from entering the intake system when the sensor is removed. Pay particular attention to the area around the sensor body and electrical connector.
3. 3

   Disconnect Electrical Connector
   Press the locking tab on the sensor electrical connector and pull the connector straight off the sensor. The tab typically lifts upward before the connector can be pulled free. Do not twist or rock the connector excessively as this can damage the pins inside the sensor body.
4. 4

   Remove Sensor Mounting Fastener
   Using the appropriate Torx driver, remove the single mounting bolt securing the boost pressure sensor to the charge air duct. The bolt threads into a plastic boss on the duct. Keep the bolt clean and inspect threads for damage. Note: Sensor mounting bolt torque per factory spec (typically approx. 5-7 Nm for M6 into plastic/insert boss — verify before applying)
5. 5

   Extract Sensor from Duct
   Carefully pull the sensor straight out of the charge air duct. The sensor is sealed with an O-ring that may cause slight resistance. If the sensor is stuck, gently rotate it while pulling to break the seal. Do not pry against the duct as the plastic can crack.
6. 6

   Inspect Sensor Port and Seal
   Examine the sensor mounting port in the charge air duct for cracks, debris, or oil contamination. Check the O-ring seal on the old sensor for compression, cracking, or deterioration. If the O-ring remained in the duct during sensor removal, extract it with a small pick or screwdriver. Wipe the port clean with a lint-free cloth.
7. 7

   Prepare New Sensor
   Verify the new boost pressure sensor has a fresh O-ring seal installed in the groove on the sensor body. If installing a new O-ring on a reused sensor, ensure it is properly seated in the groove with no twists or folds. Do not apply lubricant to the O-ring as this can attract contaminants in the intake system.
8. 8

   Install Sensor into Duct
   Align the sensor with the mounting port in the charge air duct, ensuring the orientation matches the bolt hole location. Push the sensor straight into the port until the mounting flange contacts the duct surface and the bolt hole aligns. The O-ring should compress evenly as the sensor seats.
9. 9

   Secure Sensor Mounting Bolt
   Install the mounting bolt through the sensor flange and thread it into the charge air duct by hand. Once finger-tight, use a torque wrench to tighten the bolt to specification. Do not overtighten as this can crack the plastic duct boss.
10. 10

    Reconnect Electrical Connector
    Push the electrical connector onto the sensor until the locking tab clicks into place. Tug gently on the connector to verify it is fully locked. Ensure no wires are pinched or under tension.
11. 11

    Reinstall Engine Cover and Reconnect Battery
    Position the engine cover over the engine and press down firmly on all mounting points until the rubber grommets snap into place. Reconnect the negative battery terminal and tighten the terminal bolt securely.

Reassembly

1. Reassembly is covered in the removal steps above
2. Ensure all electrical connectors are fully seated and locked
3. Verify engine cover is properly secured at all mounting points

Verification

• Start the engine and verify no diagnostic trouble codes are present using a scan tool
• Check for air leaks around the sensor by listening for hissing sounds at idle and during light throttle application
• Monitor boost pressure readings with a scan tool during a test drive to confirm sensor is functioning correctly
• Verify sensor electrical connector is dry and shows no signs of oil seepage after initial run cycle

Related trouble codes on this vehicle

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